So, Steam version places the files in the following folder:

...\Steam\steamapps\common\HonkaiImpact3rd\

If you download the game from the Hoyoverse launcher, you can freely select your installaton folder:



However, if you try to locate already installed game from Steam, you'll see this:



This is likely happening because the main game folder names are different between the Steam and Hoyoverse versions, and some file locations don’t match up.

1. First, install your game on Steam and run it at least once. HoyoPlay app should also be installed. After that go to ...\Steam\steamapps\common\ and rename the "HonkaiImpact3rd" folder to "Honkai Impact 3rd game".

2. In the HoyoPlay launcher click the "Get Game" button, and select your ...\Steam\steamapps\common\ folder. Launcher will automatically create the game folder here. Do not select the "Honkai Impact 3rd game" folder, because it will add another one with the same name inside it. Wait for the game to download.

3. Now rename the "Honkai Impact 3rd game" folder back to "HonkaiImpact3rd". Restart the HoyoPlay launcher, click the "Locate Games" button, then "Select Manually". Go to the ...\Steam\steamapps\common\ and select the "HonkaiImpact3rd" folder. Now you should see this:



4. Click the "Link Game" button, and close the launcher. Now you can start the game on Steam and log in with your Hoyoverse account.

If you did everything according to this guide, you'll need to update your game twice when the new game version comes out. First, it's automatically gets updated by Steam, and then you need to manually update it on HoyoPlay launcher. This overwrites the Steam files with the HoyoPlay version of the game, allowing you to play with your Hoyoverse account.

If you want to use Steam overlay in-game, you need to launch Steam as administrator, or set the ...\Steam\steam.exe file to always start as administrator.